As the matrix resin for composite material, there have hitherto been widely used epoxy resins for their adhesivity and high rigidity. As the high performance structural matrix resin, in particular, there has been widely used, since 1972, a composition comprising, as main components, N,N,N',N'-tetraglycidyldiaminodiphenylmethane and 4,4'-diaminodiphenyl sulfone.